Hydraulic brake control valves

ABSTRACT

The invention is an improvement in vehicle brake pressure control means of the type in which a brake pressure control valve is subject to the action of a spring load, varying with changing vehicle loading conditions, which modifies the operating characteristics (pressure reducing, pressure increasing or pressure limiting) of the valve. A coil torsion spring has opposed arms, one of which is connected to an unsprung vehicle part and the other to the sprung part. The latter arm is pivotally connected to a mounting bracket by means of a clamping member which holds the arm in rocking engagement with a fixed fulcrum.

[54] YDRAUMC BRAKE CONTROL VALVES [72] Inventor: Thomas G. Lawson, KingsRoad Tyseley,

Birmingham, England [73] Assignee: Girling Limited [22] Filed: Dec.31,1969 [21] Appl. No.: 889,763 [30] Foreign Application Priority Data Jan.2, 1969 Great Britain ..378/69 52 us. Cl "137/351 [51] lnt.Cl...B66f9/06 [58] FieldofSearch ..l37/351;280/124F [56] References CitedUNITED STATES PATENTS 2,916,284 12/1959 Bertsch et a] ..280/l24 F2,962,297 11/1960 Cislo ..280/124 F 3,026,125 3/1962 Vogel ..280/124 F[45] m 29 WW2 Primary Examiner-Samuel Scott Attorney-Scrivener, Parker,Scrivener and Clarke [57] ABSTRACT The invention is an improvement invehicle brake pressure control means of the type in which a brakepressure control valve is subject to the action of a spring load,varying with changing vehicle loading conditions, which modifies theoperating characteristics (pressure reducing, pressure increasing orpressure limiting) of the valve. A coil torsion spring has opposed arms,one of which is connected to an unsprung vehicle part and the other tothe sprung part. The latter arm is pivotally connected to a mountingbracket by means of a clamping member which holds the arm in rockingengagement with a fixed fulcrum.

8 Claims, 9 Drawing Figures PATENTEBHARNISYZ SHEET 2 0P6 Fla. 2

PATENTED MAR 2 8 |972 SHEET 3 [IF 6 PATEMTEnH/ww x972 SHEET u UF 6PATENTED MR 2 8 i972 3, 6 51 ,82 8

SHEET 5 [IF 6 N (5 it ,4 Q U m] m HYDRAULIC BRAKE CONTROL VALVES Thecomplete specification of our copending patent application Ser. .No.13830/67 (Ser. No. 1172101 French Pat. Specification No. 1,529,694)describes and claims brake pressure control means for a vehicle having asprung part and an unsprung part, comprising a pressure control valvehaving a movable member whose loading determines the operatingcharacteristics of the valve, means for mounting the valve on one of thesaid parts of the vehicle, and a control spring having a coil portion,one end of which acts on the movable member, and the other end of whichis adapted to be connected to the other of the said vehicle parts insuch a manner that, in use, variations in the loading of the vehicleeffect relative angular displacement of the ends of the spring about theaxis of the coil to vary the stress therein and the loading of themovable member.

In the above-mentioned specification, the spring has one end secured toa lever which is, in turn, journaled for rotation about a pivot pincarried by a mounting bracket for the control valve. Insome operatingconditions, however, a journal bearing of this type may become badlyaffected by corrosion and dirt, thus affecting the operating efficiencyof the control means.

The present invention provides an improved form of pivotal connection,which may be produced cheaply, and which is less vulnerable in use tothe effects of dirt and corrosion.

In accordance with the invention, there is provided vehicle brakepressure control means, for a vehicle having a sprung part and anunsprung part, comprising a pressure control valve having a movablemember whose loading determines the operating characteristics of thevalve, means for mounting the valve on one of the said parts of thevehicle, and a control spring having a coil portion, one end of whichacts on the said movable member and the other end of which is adapted tobe connected to the other of the said vehicle parts in such a mannerthat, in use, variations in the loading of the vehicle effect relativeangular displacement of the ends of the spring about the axis of thecoil to vary the stress therein and the loading of the movable memberwherein the said one end of the spring is held by a clamping memberagainst a fixed fulcrum about which the said one end of the spring canrock.

The fixed fulcrum may be formed by a fixed pivot pin and the clampingmember may be secured to the spring, close to one end thereof, with thespring and clamping member engaging over the pivot pin from oppositesides thereof so as to form a pivotal connection with the pin. Aparticularly rugged and stable assembly can be achieved by forming thespring with spaced parallel limbs extending transversely to the pivotpin, with the clamping member bridging and secured to the said limbs.

In an alternative embodiment, the spring extends through an aperture inthe mounting means and the clamping member acts to hold the springagainst an edge of the aperture in a manner which allows the spring torock about the said edge. Preferably, the end of the spring is formedwith a loop which is engaged over a fixed tongue projecting into theaperture.

Three forms of brake control means in accordance with the invention willnow be described, by way of example only, with 60 The brake controlmeans shown in FIGS. 1, 2 and 3 com- 70 prises a brake pressure controlvalve 10 having a movable member 11 and securely fixed to a mountingbracket 12 shown mounted on a sprung vehicle part such as a chassisframe member 13. The bracket carries a fixed pivot pin 14. A controlspring for controlling operation of the valve comprises a coil portion16 and two arms 17 and 18 integral therewith. The extreme end of the arm18 is pivotally connected by a shackle link 19 to an unsprung vehiclepart, such as the rear axle casing.

The extreme outer end of the arm 17 is formed with an open, partial loop21 which engages over the pivot pin 14. Secured to the arm close to thatend is a clamping means formed by a pair of clamping plates 22, 23secured together on opposite sides of the spring arm by a nut 24 andbolt 26. The plate 22 has an extension or lug 27 pressed into a partial,open loop of V-section the lug 27 and spring loop 21 being engaged overthe pivot pin on opposite sides thereof so as to form a pivotalconnection with the pin.

The outer end portion of the spring arm 17 and the clamping plates 22,23 thus form a pivoted lever by means of which valve operating forcescan be transmitted to the control valve. In this embodiment, the head ofbolt 26 forms an abutment directly engaging the movable valve member 11.

The control means shown in FIGS. 4, 5 and 6 is generally similar, exceptthat the control spring is formed in two sections A and B side by side,with their respective coil portions 16A and 168 in register butspiralling in opposite directions. The two sections are preferably (andas shown) formed from a single length of wire, but could be separate ifdesired. Also, the clamping means in this embodiment incorporates anadjustable abutment for engaging the movable valve member 11. Moreparticularly, the clamping plates 22, 23 are connected together by aninternally and externally screw threaded, headed bush 30, which receivesa nut 31. A grub screw 32 is received through the bush, one end engagingthe valve member 11, and the other being received in a lock nut 33.Axial adjustment of the grub screw, along the line of action of themovable valve member 11, enables the initial spring load applied to themovable valve member to be varied.

In both embodiments described above, the pivotal connection of thecontrol spring to the mounting bracket is achieved with a very simpleassembly which is cheap to manufacture. The clamping plates 22, 23 arepreferably formed as metal pressings, thereby avoiding the cost of amachined lever. Also, the nature of the pivotal connection is such thatit is not greatly affected by corrosion and dirt. In each case, thecontrol spring has, at its end, spaced parallel portions, both clampedbetween the clamping plates so as to produce a sturdy and stableassembly.

In the arrangement shown in FIGS. 7, 8 and 9, the mounting bracket 12 isformed with an aperture 31 having a projecting tongue 32. The adjacentend of the spring arm 17 is formed into a loop 33 which extends throughthe aperture and engages over the tongue, where it is retained by aclamping member in the form of a stop 34 of plastics or other resilientmaterial wedged in between the spring loop 33 and one edge of theaperture. The stop 34 thus holds the spring against the opposite edge 36of the aperture and this edge acts as a fixed fulcrum about which thespring arm 17 can rock. An intermediate portion of the spring arm 17 isreceived in a forked abutment 37 mounted on the movable valve member 11.

In each of the above-described embodiments, the arrangement is suchthat, in use, variations in vehicle loading which cause changes in theheight of the sprung part of the vehicle relative to the unsprung partcause angular movements of the spring arm 18 about the axis of coilportion 16, to vary the stress in the coil portion and thus the forceapplied by the arm 17 to the valve member 11.

In this embodiment, also a reliable and sturdy pivotal connection isachieved without the use of machined levers, and the connection is notgreatly affected by corrosion and dirt, since the relatively movableparts of the connection have substantially line contact only, and notfull cylindrical surface contact as in a conventional bearing.

I claim:

1. In vehicle brake pressure control means, for a vehicle having asprung part and an unsprung part, comprising a pressure control valvehaving a movable member whose loading determines the operatingcharacteristics of the valve, means for mounting the valve on one of thesaid parts of the vehicle and a control spring having a coil portion,one end of which acts on the said movable member and the other end ofwhich is adapted to be connected to the other of the said vehicle partsin such a manner that, in use, variations in the loading of the vehicleeffect relative angular displacement of the ends of the spring about theaxis of the coil to vary the stress therein and the loading of themovable member, the improvement which comprises a fixed fulcrum on saidmounting means and a clamping member acting to hold said one end of saidspring against said fulcrum for rocking motion about said fulcrum.

2. The improved control means of claim 1, wherein said fixed fulcrum isconstituted by a fixed pivot pin carried by said mounting means, andsaid clamping member is secured to said spring close to one end thereof,said spring and clamping member being engaged over said pin fromopposite sides thereof to form a pivotal connection therewith.

3. The improved control means of claim 2, wherein said spring is shapedto have spaced parallel limbs extending transversely to said pivot pin,and said clamping member bridges said limbs and is securely clampedthereto.

4. The improved control means of claim 2, wherein said spring and saidclamping member are each formed with a partial open loop engaging oversaid pivot pin.

5. The improved control means of claim 2, comprising an abutment securedto said clamping member and spaced from said pivot pin for engagementwith said movable member of said control valve.

6. The improved control means of claim 5, comprising means for adjustingsaid abutment, relative to said clamping member, along the line ofaction of said movable member.

7. The improved control means of claim 1, wherein said mounting means isshaped to define an aperture having an edge, said one end of saidcontrol spring extends through said aperture, and said clamping memberis operative to hold said spring engaged against said edge, whereby saidedge constitutes said fixed fulcrum.

8. The improved control means of claim 7, wherein said mounting meanshas a tongue projecting into said aperture from said edge and said edgeand said one end of said spring is shaped to form a loop engaged oversaid tongue.

1. In vehicle brake pressure control means, for a vehicle having asprung part and an unsprung part, comprising a pressure control valvehaving a movable member whose loading determines the operatingcharacteristics of the valve, means for mounting the valve on one of thesaid parts of the vehicle and a control spring having a coil portion,one end of which acts on the said movable member and the other end ofwhich is adapted to be connected to the other of the said vehicle partsin such a manner that, in use, variations in the loading of the vehicleeffect relative angular displacement of the ends of the spring about theaxis of the coil to vary the stress therein and the loading of themovable member, the improvement which comprises a fixed fulcrum on saidmounting means and a clamping member acting to hold said one end of saidspring against said fulcrum for rocking motion about said fulcrum. 2.The improved control means of claim 1, wherein said fixed fulcrum isconstituted by a fixed pivot pin carried by said mounting means, andsaid clamping member is secured to said spring close to one end thereof,said spring and clamping member being engaged over said pin fromopposite sides thereof to form a pivotal connection therewith.
 3. Theimproved control means of claim 2, wherein said spring is shaped to havespaced parallel limbs extending transversely to said pivot pin, and saidclamping member bridges said limbs and is securely clamped thereto. 4.The improved control means of claim 2, wherein said spring and saidclamping member are each formed with a partial open loop engaging oversaid pivot pin.
 5. The improved control means of claim 2, comprising anabutment secured to said clamping member and spaced from said pivot pinfor engagement with said movable member of said control valve.
 6. Theimproved control means of claim 5, comprising means for adjusting saidabutment, relative to said clamping member, along the line of action ofsaid movable member.
 7. The improved control means of claim 1, whereinsaid mounting means is shaped to define an aperture having an edge, saidone end of said control spring extends through said aperture, and saidclamping member is operative to hold said spring engaged against saidedge, whereby said edge constitutes said fixed fulcrum.
 8. The improvedcontrol means of claim 7, wherein said mounting means has a tongueprojecting into said aperture from said edge and said edge and said oneend of said spring is shaped to form a loop engaged over said tongue.